The PICL V2 - a development of Karen's 2007 original

[Michael Haardt]

What is kitbug+ ? I have kitbug, built from original source, but never knew that was a newer version.

Michael

[Phil__G]

Hi Michael, KB+ is a simple 1k monitor I did for the PICLV2, its typical of the late 70s period with modify, list, display, hexload, registers display, go (run), nibl, etc. It has some new elements, some from my own monitor for the David Aitken SCMP, and some from the original Kitbug, hence Kitbug+. There's a bit of a demo in the video linked in the first post of this thread
Cheers
Phil

[Phil__G]

..sorry Michael, I should have said, KB+ is pretty much tied to the PICLV2 as some routines like hexload and stand-alone auto-run are dependent on the updated pic code

[Michael Haardt]

That is a pity, a better monitor for real SC/MP systems would be nice.

Michael

[Michael - K8LH]

Originally Posted by Phil__G

PS dont forget that the two halves of the 8k ram holding pages 1 & 2 are reversed... page 1 physically lives in the top half, page 2 in the lower 4k. This is only noticable when dumping the ram on a TL866 etc, in practise the PIC code straightens it out, but it could be the source of a 'Gotcha' when reworking... its like Karen inverted RAM A12 for some reason.

I noticed that early on. Using only 13 address lines produces several 8K mirrors across the 64K address space and since NIBL ROM is inserted into Page 0 ($0000..$0FFF) we are actually reclaiming Page 0 RAM by using a mirror of it in the Page 2 address space ($2000..$2FFF).

My 32K PICL Release 2 ('R2') update mirrors the 32K RAM at $8000..$FFFF and since Page 0 RAM ($0000..$0FFF) is replaced by NIBL ROM, we reclaim the use of that 4K block of RAM by using its mirror in Page 8 ($8000..$8FFF).

Mike

[Michael - K8LH]

A quick question about NIBL BASIC, please?

Does NIBL BASIC only support pages 1 through 7 (only the lower 32K of memory) as the documentation suggests?

TIA... Cheerful regards.

[Phil__G]

Yes thats right Mike, and it has an extra peculiarity in that if page 2 is read-only AND contains a valid NIBL program, then it automagically runs on switch-on

[Michael - K8LH]

Fascinating! I'll have to test that (copy an image including a BASIC program from flash memory into page 2 RAM memory at startup and then write protect that page before launching SC/MP + NIBL).

May I ask if you've tried to 'save' and 'load' BASIC files to/from NIBL pages and Terminal as Hex files? I'm thinking about re-tasking Reset + Sense B by replacing the current "download HEX file" function with <Load>, <Save>, and <Flash> commands (with [source] and [target] parameters). I really wouldn't mind having a <Memory Test> command, too, or the capability to burn new firmware into the PIC from a HEX file that has been downloaded into RAM memory.

Cheerful regards...

[Phil__G]

Write protecting page 2 didn't work for me Mike, that's how I found the swapped pages, but that could easily have been that I messed up! You could of course save/load NIBL progs with Intel hex but it's half speed two hex chars for every basic char. Sense B on power up could bring up a menu with as many options as you like, my personal idea was that it should remain a PICL

[Michael - K8LH]

Phil: The NIBL "auto run" feature is working (see below). I just included a short BASIC program in the PIC "page 2 image" that's loaded into RAM at startup and I write protected 2000..27FF instead of the whole 4K page because Kitbug+ needs to be able to write the register area just below 2C00. Now that we have more than 8K RAM, I wonder if Kitbug+ could reside in another page to allow best use of the NIBL page 2 "auto run" feature?

HEX files are longer but should load much faster than loading BASIC programs as text files with long inter-character and end-of-line delays in your Terminal program. Remember, too, serial is 9600 baud on the PICL 'R2'.

Please keep in mind that the SC/MP emulator and NIBL BASIC are virtually unchanged. Enhancing the current "download HEX file" feature with additional capability shouldn't detract from the operation and/or PICL/NIBL experience and I believe it's a reasonable alternative to purchasing an expensive nvRAM chip.

Stay safe. Regards...

[Phil__G]

Great progress Mike, I was going to suggest shifting KB+, in 8k it made sense to locate it just below the ceiling but with 32k it could go anywhere. Re the hex save/load I dont think the speed really matters that much, back in the day NIBL was 110 baud and 300 baud was super fast! I got around the NVRAM expense using cheap-as-chips ram and a DS1210, not as neat but works great for any of the 6264, 62256, 43256, UM61512, AS6C1008, etc - in fact on some NVRAMS you can see a DS1210 underneath!
Cheers
Phil

[Michael - K8LH]

I commissioned a PICL 'R2' 32K RAM PCB that supports the use of skinny, wide, SIP, or ZIF sockets for RAM. Unfortunately, the board was ordered just before I came up with the 1-pin Serial Port mod' so there will be one more iteration of the 'R2' PCB design coming up.

regards...

[Phil__G]

Looking good Mike, I must order some 18877's in readiness!
Somehow I missed your 1-pin serial post and the KB+ demo post, caught up now
Been distracted, playing with ESP32's and making internet radios
https://www.dailymotion.com/video/x87ex4i


.

[Michael - K8LH]

Wow... the ESP32 Internet Radio looks really nice, Phil. Bravo!

I apologize for distracting you from your current projects.

I've attached updated PICL 'R2' Gerbers if you're interested in getting some boards. I'm still adding to the PIC firmware. And, I'll start a new thread for the 'R2' instead of messing up your 'V2' thread.

Take care. Cheerful regards...

ps: your "light show" program is delightful...

[Phil__G]

No Mike I meant the esp32s were the distraction
Having a bit of a mojo lull at the moment, although I've started an email exchange with a Dutch SC/MP enthusiast, we're just exchanging our stories at the moment
...and I have some RCA1802 PCBs on order

[Phil__G]

Really neat layout Mike, do I see a cunningly concealed DS1210?

[Michael - K8LH]

Originally Posted by Phil__G

Really neat layout Mike, do I see a cunningly concealed DS1210?

That DIP-8 footprint could be used for a DS1210 (I have some on order) or perhaps a 128-KiB I2C EEPROM chip.

Could I impose on you once more for some 'tech talk', please?

I'm back to working on PIC firmware to simply upgrade the PIC CPU on your 'standard' 8K RAM board.

Would you consider modifying your fantastic Kitbug+ Monitor to run in NIBL Page 4 ($4C00..$4FFF) or Page 6 ($6C00..$6FFF)? I ask because I'd like to experiment with NIBL Page 2 ($2000..$2FFF) write protected (see below) and Kitbug+ running at $2C00..$2FFF would not be able to write anything in page 2. Fortunately, Page 2 is mirrored in Page 4 and Page 6 which are not write-protected. So while Kitbug+ will still physically reside in Page 2, it will run (and be able to write) in the Page 4 or Page 6 mirror.

Cheerful regards...

;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
;  Write memory macro. For page 0 use only.                       ~
;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
WRMEM   macro   PHI,PLO         ;                                 |
        movf    PHI,W           ; target address hi               |
;       andlw   b'11110000'     ; ROM ($0xxx)?                    |
        andlw   b'11010000'     ; ROM ($0xxx) or Page 2 ($2xxx)?  | <---
        skpnz                   ; no, skip (write enabled), else  |
        return                  ; return (write protected)        |
        WRRAM   PHI,PLO,ACC     ; write RAM                       |
        return                  ;                                 |
        endm

[Phil__G]

Hi Mike, check your email please

[Michael - K8LH]

Got it. Thank you. Sorry for late reply. Indeed, that code works great.

Work is progressing nicely... Only a couple snags which require some more research in the NIBL listings. One 'snag' is that NIBL clears programs in pages 1 through 7 on a cold start and while it isn't able to clear the program in the write protected page 2 it does clear the 'mirror' of the program in page 4 which effectively clears the real program in page 2. Bummer. Fortunately, modifying one byte in NIBL will limit this "search and destroy" operation to pages 1 and 2 on 8K PICL boards.

Cheerful regards, Mike

[Michael - K8LH]

Hey Phil:

That "green screen" Tera Term image is soooo retro' and reminds me of my first monochrome monitor. My Tera Term setup now has a green screen, too (grin)...

Regards...